Increasingly, people are using mobile computing devices to consume media. Generally, battery life is limited. Once the battery is depleted, the mobile device will shut down and cannot be restarted until a plug can be found or a new battery is provided. This is very frustrating as a user cannot use the mobile device while the battery is drained. Additionally, there are times where the user is only using a certain portion of the display, yet a large amount of energy is expended to light the entire display, which may result in faster battery depletion.
On modern personal computing systems, the display is a significant power consumer and the power consumed by a liquid crystal display (“LCD”) backlight far exceeds the power consumed by the LCD itself. Additionally, backlight systems using Cold Cathode and Hot Cathode Fluorescent Lamp (CCFL/HCFL) sources also consume a significant amount of power relative to other components of the computer. Even a small power consumption savings in the backlight may result in the user able to use the mobile device for an extended period of time, which is advantageous.